In the coming year we expect to complete our study of the scleral spur. Mobility of the spur will be investigated by severing its anterior tether, namely the trabecular meshwork. We already have evidence that after trabeculotomy in vitro and in vivo the wound gapes, implying that the elastic choroid and ciliary body pull the spur posteriorly. These findings will be elaborated. The frequency with which blood can be refluxed into the canal of Schlemm of healthy eyes will be enhanced if possible. Blood reflux in eyes with various degrees of spontaneously occurring elevation of intraocular pressue will be studied to see if evidence of canal collapse can be adduced. Such evidence would be tapering of the anterior portion of the refluxed blood column and reduced ability to produce visible reflux. The low-pressure tonography system is still under construction. This will be completed and tests on normals will be contrasted with tests on eyes with early glaucoma to see if separation of the groups is better than with conventional tonography.